Crankshaft main bearing caps used in internal combustion engines can create a blockage between engine bays that results in a reduction in oil movement through the crankcase and increased localized crankcase pressures. The reduced oil movement between bays can cause excess pressure buildup below the pistons and rob the engine of horsepower.
A current solution is to machine an undercut breathing window in the main bearing cap blanks, whether made of powder metal or cast iron. The undercut feature or window aids in the breathing or movement of oil from one bay in the engine to the other, thereby reducing internal engine pressures and increasing horsepower. Machining in this feature however is time consuming and costly.